I choose the first of the marked three in this list

They are all the same size. No element above - animation is triggered by clicking the animation element. 
When the animation frames are not the same size, we add a dot at 2 corners.
The scaling down is quite consistant - didn't anyone every notice that ?
Ranco

When I load a PSD file with frame animation, for the second time (same page, after changes in the PSD, for example), either the animation is duplicated (Frame001, Frame001, Frame002, Frame002, ...) or I get this error when clicking "Frames" under Props:

InteractBuilder Version: 3.3 Build 325
Device: System Product Name
Processor: 1 Processor(s) Installed.
[01]: x64 Family 6 Model 23 Stepping 10 GenuineIntel ~1999 Mhz
Memory: 3,327 MB
System: NT 6.1
--------------------
An application error occurred while attempting to perform the last action.
Restarting InteractBuilder is recommended.
An application error occurred while attempting to perform the last action.
Restarting InteractBuilder is recommended.
Error: Chunk: can't find background / Chunk: can't find object / Object: does not have this property / Operators +: error in left operand / put: error in expression
Handler: PopOverMenu_ShowSubMenu
Hint:
Location: Line 4465, char 23
Object: button id 380192 of card id 1002 of stack "IBResources" of stack "C:/Program Files/InteractBuilder/Local Components/Data/InteractBuilder.livecode"
87: Line 4465 at char 23: Chunk: can't find background
77: Line 4465 at char 23: Chunk: can't find object
456: Line 4465 at char 15: Object: does not have this property
394: Line 4465 at char 64: Operators +: error in left operand
465: Line 4465 at char 1: put: error in expression
253: Line 4464 at char 1: if-then: error in statement
253: Line 4461 at char 1: if-then: error in statement
241: Line 4461 at char 1: Handler: error in statement ----> PopOverMenu_ShowSubMenu
353: Line 0 at char 0: Object Name: ----> button id 380192 of card id 1002 of stack "IBResources" of stack "C:/Program Files/InteractBuilder/Local Components/Data/InteractBuilder.livecode"
line 150 of handler "errorDialog" of button "stsErrors_FS" of card id 1002 of stack "libSTSErrors"
line 14245 of handler "DoError" of stack "InteractBuilder" of behavior button "Stack B" of card id 1002 of stack "Behaviors"

I just found out that the correct image is after the click. Meaning - the image I see before the first animation is a bit larger than frame 001 of the animation.

Sure, it happens all the time.
Ranco

No, sorry, it's not. Once it happens (when leaving interact mode to Design), no element can be clicked and edited. They all generate the same error.

Well, it's not a specific element, it's every element I click. Nothing special, and it should be quite easy to reproduce because it happens A LOT. (maybe you should try on Windows...)
Ranco